The development of renewable bio-based chemicals has the potential to reduce the amount of petroleum consumed in the chemical industry and also to open new high-value-added markets to agriculture; 1,4:3,6-dianhydrohexitols are examples of such chemicals.
Interest in the production of 1,4:3,6-dianhydrohexitols, especially isosorbide, has been generated by potential industrial applications including the synthesis of polymers such as notably polyesters, polyethers, polyurethanes and polyamides. The use of 1,4:3,6-dianhydrohexitols in polymers, and more specifically in polycondensates, can be motivated by several features: they are rigid molecules, chiral, and non-toxic. For these reasons, there are expectations that polymers with high glass transition temperature and/or with special optical properties can be synthesized. Also the innocuous character of the molecules opens the possibility of applications in packaging or medical devices.
The industrial production of such monomers is a developing area, quickly making available this feedstock at more and more attractive prices. Moreover, interest in chemicals derived from renewable resources is increasing and becoming a decisive argument: as the carbon contained in bioplastics is not derived from fossilized biomass, but from atmospheric CO2 absorbed by vegetals biomass, these plastics should alleviate the effects of climate change.
Depending on the chirality, three isomers of the 1,4:3,6-dianhydrohexitols sugar diol exist, namely isosorbide (1), isomannide (2) and isoidide (3):

The 1,4:3,6-dianhydrohexitols are composed of two cis-fused tetrahydrofuran rings, nearly planar and V-shaped with a 120° angle between rings. The hydroxyl groups are situated at carbons 2 and 5 and positioned on either inside or outside the V-shaped molecule, as shown in scheme 1. They are designated, respectively, as endo or exo. Isoidide has two exo hydroxyl groups, whereas for isomannide they are both endo, and for isosorbide there is one exo and one endo hydroxyl group. It is generally understood that the presence of the exo substituent increases the stability of the cycle to which it is attached. Also, exo and endo groups exhibit different reactivities since they are more or less accessible depending on the steric requirements of the studied reaction. The reactivity also depends on the existence of intramolecular hydrogen bonds.
As per the manufacture of these 1,4:3,6-dianhydrohexitols, to summarize briefly, starch extracted from biomass and in particular from corn starch, is first degraded into d-glucose (1.A) and d-mannose (2.A) by an enzymatic process. The hydrogenation of these two sugars gives d-sorbitol (1.B) and d-mannitol (2.B); sorbitol and mannitol can subsequently be dehydrated to obtain isosorbide (1) and isomannide (2), as shown herein below:

Finally, the third isomer, isoidide (3), can be produced from 1-idose following a similar procedure as above sketched, but 1-idose rarely exists in nature and cannot be extracted from vegetal biomass. For this reason researchers have developed different pathways to isoidide, including isomerisation of isosorbide or isomannide.
Kricheldorf et al. first reported the preparation and characterization of poly(ether sulfone)s containing isosorbide from silylated isosorbide and difluorodiphenylsulfone (DFDPS) in 1995 (H. Kricheldorf, M. Al Masri, J. Polymer Sci., Pt A: Polymer Chemistry, 1995, 33, 2667-2671). Since the silylation step adds significant cost, Kricheldorf and Chatti (High Performance Polymers, 2009, 21, 105-118) modified their polymerization conditions and reported that poly(ether sulfone)s containing isosorbide could be made from pure isosorbide and DFDPS. The highest apparent molecular weight polymer obtained had an inherent viscosity (IV) of 0.65 dL/g, said IV was measured according to following conditions: CH2Cl2/trifluoroacetic acid solution (9/1 v/v) at 20° C., 0.20 dL/g. The glass transition temperature of this polymer was reported as 245° C. No examples were described where the polymerization reaction with isosorbide was conducted with the less reactive dichlorodiphenylsulfone (DCDPS).
There is still a need in the art for an efficient process for the manufacturing of poly (arylether sulfone)s (PAES) polymers comprising recurring units derived from bio-compatible and bio-based raw materials and a variety of dihaloaryl compounds comprising at least one SO2 group, whereby said (PAES) polymers are characterized by having high molecular weights (Mw); having excellent thermal stability, high stiffness and strength, good toughness and attractive impact properties; allowing to provide improved performance relative to current commercial PAES grades for applications such as membrane, medical, aerospace, automotive applications.